This invention relates to an ultrasound device and, in particular, to a disposable ultrasound probe insertable into a body cavity to enable ultrasound insonation of internal vessels and organs. Aspects of the invention may, however, be applied to other non-invasive ultrasound devices such as those which are placed in contact with the body outer surface.
Ultrasound is widely used in medicine for imaging and/or diagnostic purposes. In one form of device, ultrasound transmit and receive crystals are mounted on the tip of a probe which, in use, is located within the body so that specific organs or vessels can be subjected to ultrasound insonation and the reflected signals then analysed to give particular diagnostic information. In another form of device, the transmit and receive crystals are mounted in contact components designed to be held in contact with the body outer surface adjacent the organs or vessels to be insonated.
This company has, for some time, been manufacturing and selling an instrument for determining cardiac function. This instrument incorporates a disposable probe which is inserted into the patient""s oesophagus, the probe having mounted on the outer end thereof, ultrasound transmit and receive crystals. In use, the probe is aligned so that the crystals are aligned substantially at 45xc2x0 to the patient""s descending aorta and are thus arranged to insonate a section of the descending aorta with ultrasound.
The probe is specifically designed and intended as a disposable device yet medical staff will, in some situations, still attempt to re-use probes on other patients. This practice carries with it a risk of cross-infection. Further, successive sterilisations intended to reduce the risk of cross-infection, can lead to a breakdown of the probe components which are not designed for such treatment.
A further characteristic of these disposable probes is that the level of ultrasound to which the patient is subjected, will vary from probe to probe. Typically this is because the receive and transmit crystals are mass manufactured from commercial grade materials and are thus susceptible to quality, and thus performance, variations.
It is therefore an object of this invention to provide an ultrasound device which will go at least some way in addressing the above-mentioned drawbacks, or which will at least provide a useful choice.
Accordingly, in one aspect, the invention provides a method of controlling the use of a disposable ultrasound device used in conjunction with a host processor to monitor physiological behaviour of a human subject, said method including the steps of:
storing acceptable use parameters in electronic memory embodied within said disposable device;
causing said host processor to communicate with said electronic memory; and
controlling the ability of said host processor to function in conjunction with said disposable device in response to variations or attempted variations arising in said use parameters.
Preferably said method includes storing in said electronic memory an acceptable total time of use of said disposable device, and preventing said host further operating in conjunction with said device when said device has been in use for a time equal to said acceptable total time.
Preferably said method includes storing patient physical data within said electronic memory and preventing said host processor from communicating any variation in said patient physical data to said electronic memory. Said patient physical data may include weight, height and/or age.
Preferably said method includes causing a host processor to record a date of first use of said device in said electronic memory, and causing a host processor to no longer function with said device at a predetermined time after said date of first use.
Preferably the date of manufacture of said device is recorded in said electronic memory, said method including causing a host processor to no longer function in conjunction with said device after the passage of a predetermined period of time after said date of manufacture.
In a second aspect the invention provides an ultrasound device for use in conjunction with a host processor to monitor physiological behaviour of a human subject, said device including electronic memory able to communicate with said host processor when said device is in use, said electronic memory being constructed and arranged to store patient use data parameters.
Preferably said electronic memory is operable to store information relating to the accumulated time of use of said device. More preferably said electronic memory contains a counter of remaining time available for use, said counter declining whilst said device is in use until zero is reached after which said device will no longer function in conjunction with a host processor.
Preferably said electronic memory contains a plurality of time counters, said host processor maintaining a host counter internally initiated from that one of said time counters in electronic memory indicating the lowest remaking time of use, said host processor updating the permissible remaining time of use alternatively between said time counters in memory.
Preferably said electronic memory is further operable to store patient physical details such as weight, height and/or age.
Preferably said device comprises a probe insertable into a body cavity.
Preferably said probe includes a connector for connection thereof to said system processor, said electronic memory means being included in said connector.
Preferably said electronic memory means comprises an E 2PROM.
Said probe may include one or more further transducer[s]operable to monitor predetermined patient parameters. Such parameters may, for example, comprise temperature or pulse oxygen levels.
In a third aspect the invention provides a Doppler ultrasound cardiac function monitor including an probe as hereinabove set forth locatable in the oesophagus of a human; and a host processor connectable to said probe, said host processor being constructed and arranged to communicate with said electronic memory and to render said monitor inoperable in response to predetermined variations or attempted variations arising, in real time, to one or more parameters stored in said electronic memory.
In a fourth aspect the invention provides an ultrasound device for insonating part of a human subject, said device including ultrasound transmit and receive means as well as at least one other transducer operable to monitor a physiological parameter of a human subject.
Preferably said transducer is operable to monitor said physiological parameter during operation of said ultrasound transmit and receive means.
In a fifth aspect the invention provides a method of calibrating an ultrasound transmit and receive device used in conjunction with a human subject, said method including the steps of associating electronic memory means with said device; subjecting said device to a signal of known characteristics; and storing the response of said device to said signal in said electronic memory.
Many variations in the way the present invention can be performed will present themselves to those skilled in the art. The description which follows is intended as an illustration only of one means of performing the invention and the lack of description of variants should not be regarded as limiting. Wherever possible, a description of a specific element should be deemed to include equivalents thereof whether in existence now or in the future. The scope of the invention should be limited by the appended claims alone.